Tank construction



Oct. 23, 1962 D. 5. R088 ETAL TANK CONSTRUCTION 6 Sheets-Sheet 1 Filed Oct. 25, 1960 INVENTORS W M $0,53 $4100 6 0,515 31 W gmfl dwm) ATTORNEYS Oct. 23, 1962 D. 3. R088 ETAL 3,059,243

TANK CONSTRUCTION Filed Oct. 25, 1960 6 Sheets-Sheet 2 INVENTORS BY W4) /y MM) ATTORNEYS Oct. 23, 1962 D. s. ROSS ETAL 3,059,243

TANK CONSTRUCTION Filed Oct. 25, 1960 6 Sheets-Sheet 3 Ag INVENTOR-S "IIIIIIIIIIIII".

ATTORNEYS Oct. 23, 1962 D. s. ROSS ETAL TANK CONSTRUCTION 6 Sheets-$heet 4 Filed 001;. 25, 1960 Oct. 23, 1962 D. 5. R085 ETAL TANK CONSTRUCTION 6 Sheets-Sheet 5 Filed Oct. 25, 1960 IN VENTORS JAM/0,67 B055 9 9 Mw ATTORNEYS Oct. 23, 1962 Filed Oct. 25, 1960 D. 5. R058 ETAL TANK CONSTRUCTION 6 Sheets-Sheet e Ill ATTORNEYS United States Patent Ofiice 3,959,243 Patented Oct. 23, 1962 3,059,243 TANK CONSTRUCTION David S. Ross and Gene W. Ross, Lorain, Ohio, assignors, by mesne assignments, to The Amcodyne Corporation, Lorain, Ohio, a corporation of Delaware Filed Oct. 25, 1960, 'Ser. No. 64,785 22 Claims. (Cl. 4-172) The present invention relates to a tank construction and, more particularly, to construction of large tanks such as swimming pools, filtration tanks, reservoirs, sewage tanks and the like.

The present invention contemplates construction of a tank from prefabricated panels which may be assembled into any desired shape or dimension. The panels may be metallic, prefabricated concrete, plastic, or a combination of metal, concrete and plastic. Throughout the specification, for purposes of illustration only, the panels will be referred to as metallic panels. While the specification will refer to a tank construction particularly adapted for use as a swimming pool, it will be understood it is within the scope and spirit of the invention that such tank construction may have other uses such as a filtration tank, sewage tank, reservoir or the like.

It has been heretofore proposed to construct tanks such as swimming pools from prefabricated metal panels, the panels forming the walls of the tank and the bottom being generally constructed of reinforced concrete. Such prior tank constructions have required substantial expane for erection as well as the necessity of extremely skilled labor in order to properly align the panels prior to connection of the panels to each other. Further, such prior prefabricated tank constructions have not completely eliminated the problem of expansion and contraction caused by variations in temperature. Such prior tanks have been constructed to compensate for variation of ground movement by the inherent flexibility of the panels per se. The joints between the panels have been substantially rigid and consequently no uneven expansion or contraction between adjacent panels could be accommodated.

An object of the present invention is to provide a tank construction wherein prefabricated metallic panels forming the side Walls of a tank may be easily erected, supported and leveled with respect to one another prior to the connecting of the panels together.

Another object of the present invention is to provide a tank construction having prefabricated panels capable of being erected by relatively inexperienced personnel in a minimum time with a minimum of equipment.

Still another object of the present invention is to provide a tank construction for erection in an excavation wherein the prefabricated panels may be adjusted from inside of the tank thereby reducing the amount of excavation and the amount of back fill necessary after erection of the side walls of the tank and pouring of the bottom.

A further object of the present invention is to provide a tank construction made from a plurality of prefabricated metallic panels, the joints between the panels being water tight yet capable of accommodating for expansion and contraction regardless of whether expansion and contraction at the joint is uneven. In this respect, expansion and contraction caused by variations in temperature is almost never even as water has a tendency to retain its temperature while the temperature may differ at different levels of the surrounding ground. Consequently, uneven stresses and strains occur on the'panel sections and on the joints between the panel sections and such uneven expansion and contraction is compensated for by the novel water-tight expansible joint between panel sections of the tank construction of the present invention.

A still further object of the present invention is to 2 provide a tank construction for swimming pools or the like which is constructed from metal prefabricated panels, the metal panels forming a relatively smooth uninterrupted side wall having a relatively smooth upper edge which fairs in with the decking provided about the pool.

Population of communities is constantly changing. The increased growth of communities oftentimes causes the communities considerable expense in expanding their present equipment to meet such growth. For example, a tank constructed for a particular community is designed to accommodate the population of that community for a number of years. Because of population growth oftentimes is more rapid than anticipated, the serviceability of the tank cannot accommodate the needs and is obsolete within a few years. Consequently the community must provide additional tanks and construction of additional tanks is quite expensive. In communities utilizing sewage tanks, filtration tanks, reservoirs or the like and even swimming pools, it has been found that to provide additional facilities even though not as large as the original facilities, cost is as much as the cost of the original facilities. The present invention contemplates the construction of a tank which may be easily expanded to accommodate future needs of the community. Therefore, an additional object of the present invention is to provide a tank construction wherein the tank may be periodically expanded by enlarging the original excavation and adding to the tank an additional bottom and prefabricated side wall panels.

Heretofore water has been supplied to swimming pools at a level below the normal level of the surface of the water in the pool as it was thought necessary in order to retain the proper amount of chlorine entrained in the water. The present invention contemplates supplying water to the swimming pool from a level above the normal water level, the water being supplied at an angle to the side walls of the pool as that it impinges on the side walls at a level adjacent to the normal level of the water in the pool. Such a supply of water about the perimeter of the pool adds to the aesthetic appeal of the pool to the swimmers because of the continual motion and sound effect given to the water within the pool. Further, such a distribution of water into the swimming pool provides for a more hygienic swimming pool in that it eliminates any dead and stagnant areas of surface water as well as imparting a washing down effect to the pool side walls. The aeration caused by the jet action of the water entering the pool suppresses the growth of pathogenic (disease producing) anaerobic bacteria and algae as well as increases the clarity of the water such as, but not limited to, iron removal by oxidation and filtration of these oxides. By utilizing a jet spray, chlorine concentration or other chemical additives at the top surface of the swimming pool is more effectively maintained in an area where the maximum amount of impurities exist. The action of the jet spray tends to disturb the surface tension of the water,'thus allowing the contaminants floating on the surface of the water to be drawn below the water sur face, thus enveloping the contaminant with the chemicals present in the pool body.

An object of the present invention is to provide a handrail for aswimming pool which functions as a means for distributing water to the swimming pool and also functions to control the splash out of water over the sides of the pool.

An object of the present invention is to provide a handrail readily accessible and easily grasped by swimmers of all ages without the possibility of hands contacting pool contaminants ever present in conventional swimming pool scum gutters. This handrail provides for safe ingress and egress from the pool.

Still another object of the present invention is to pro- I 3 vide an improved filtration system for a swimming pool wherein water is skimmed from the top surface of the pool for recirculation through a filter and back into the pool.

Ancillary to the preceding object, it is another object of the present invention to provide an improved weir construction for use in the skimming means of the filtration system whereby debris skimmed from the pool is prevented from returning to the pool.

Still another object of the present invention is to provide an improved filtration system having a slurry tank with agitating means therein for constantly maintaining the diatomite in solution with water from the pool so that the water with diatomite in solution therewith may be delivered to the filtering elements.

Still another object of the present invention is to provide a weir for use with a skimming means for a swimming pool, the weir being provided with a buoyant fioat means which may be adjusted for various flow conditions.

These and other objects and advantages of the present invention will appear more fully in the following specification, claims and drawings in which:

FIGURE 1 is a perspective view of a tank construction such as a swimming pool made according to the present invention, the figure being partly broken away for purposes of clarity;

FIGURE 2 is an enlarged vertical sectional view taken through one of the panel sections of the present invention and illustrating the novel leveling means for the same;

FIGURE 3 is a fragmentary perspective view illustrating the novel expandable joint between panel sections of the present invention;

FIGURE 4 is a view taken substantially on the line 44 of FIGURE 3;

FIGURE 5 is an enlarged fragmentary top plan view of the joint of FIGURE 3;

FIGURES 6 through 10 inclusive disclose typical panel elements constructed according to the present invention for making a swimming pool such as that disclosed in FIGURE 1;

FIGURE 11 is an enlarged fragmentary vertical sectional view through a modified form of tank construction utilizing a metallic bottom;

FIGURE 12 is an enlarged fragmentary sectional view through the novel skimming means of the present invention and illustrating the improved weir construction;

FIGURE 13 is a sectional view taken substantially on the line 1313 of FIGURE 12;

FIGURE 14 is an enlarged perspective view of a buoyant float element used with the weir of FIGURE 12; and

FIGURE 15 is a schematic view illustrating the filter box of the present invention and in detail the novel slurry tank for maintaining the dia-tomite in suspension in water removed from the pool.

Tank Construction Referring now to the drawings wherein like characters and reference numerals represent like and similar parts, the swimming pool illustrated in FIGURE 1 employs the present invention of tank construction wherein the side walls of the pool are a plurality of prefabricated metallic panels secured together to the bottom in watertight relationship. The panels are preferably made of mild steel plate and are factory sand blasted on the outside which faces the dirt or back fill. A protective coating is applied to the sand blasted outside at the factory and the joints between the panels are further coated after erection and assembly. The inner side of the panels are smooth and may be either factory or field finished to any desirable decorative and protective finish.

In more detail, FIGURE 1 illustrates a swimming pool generally designated by the numeral 10 and including panel-like wall assemblies 12, 14, 14', 16, 18, 18', 2t) and 22. While the pool 10 is illustrated as a rectangularshaped pool made of three panel-like wall assemblies forming each longitudinal side wall and one panel-like wall assembly forming each end side wall, the construction of a pool from the wall assemblies of the present invention may assume various shapes and also may assume a larger size by the installation of more assemblies.

The swimming pool 10 shown in FIGURE 1 is provided with a shallow end portion 24 and a deep end portion 26, the end portions 24 and 26 forming the bottom 23 of the pool. The bottom 23 is made from reinforced concrete after the side panels, 12, 14, 14, etc. have been erected and joined together. A suitable hydrostatic pressure relief valve 28 may be provided in the bottom of the pool to eliminate the pool popping out of the ground due to pressure beneath the pool caused by various climatic conditions or by changes in the water table of the surrounding terrain. The swimming pool 10 is provided with a suitable drain 30 in its deep portion 26 as well as skimming means 32 positioned about the periphery adjacent the normal level of water in the pool. A more detailed description of the skimming means 32 and the filtration system for the swimming pool 10 will appear more fully later in the specification.

Suitable hardware for the swimming pool 19 is provided such as the ladders 34 at the shallow and deep ends and the diving board 36. In addition, the pool 10 is provided with a handrail 38 which may extend around the entire or a portion of the perimeter of the pool, the handrail 38 also furnishing a means for distributing water to the pool when the recirculating filtering system is in operation. A more detailed description of the handrail and its utility and advantages will appear later in the specification.

Wall assemblies 12, 14, as well as 18 and 20 are respectively joined to each other by a novel expansible joint generally designated at 40. The joint 44 compensates for any expansion or contraction regardless of whether it may be even or uneven so that complete compensation does not have to be within the panel of the wall assembly per se. In other words, while the metallic panel-like wall assemblies have a certain amount of flexibility capable of compensating for movement of the ground caused by variation in temperature or the like, the panel-like wall assemblies cannot completely compensate for expansion or contraction when the pool is of a relatively large size. Stresses and strains incident to alternate freezing and thawing of the ground can be completely compensated for by the novel construction of wall assemblies and joint construction of the present invention so that the pool will remain a water-tight enclosure at all times without the possibility of leakage at the joint.

Referring now to FIGURES 2 and 6 to 10 inclusive, the wall assemblies 12, 14-, 14', '16, etc. are substantially identically constructed except for their dimensions and for the cut-outs provided therein for the skimming means 32 (FIGURES l and 12), night lighting equipment and the like. In FIGURES 6 to 10 typical shapes of the wall assemblies are shown for making the swimming pool 10 of FIGURE 1. In FIGURE 6 the end wall assembly 16 is shown and it will be noted that the panel 42 of this section is a substantially rectangular shape. FIGURE 7 illus trates a tapered panel such as the panel 14 and the height of the smallest end is the same as the height of the end wall assembly 16. Section 18 is a mirror image of section 14' and likewise is adapted to connect to the end wall assembly 16. FIGURE 8 illustrates another tapered wall assembly '14 which has a height at its smallest end equal to the height of the largest end of the tapered wall assembly 14'. The joint between the sections 14 and 14' as indicated at 44 in FIGURE 1 may be either a rigid joint or an expansible joint such as the joint 40 which will be described later in the specification. Tapered wall assembly 18 is a mirror image of the wall 14 and is designed to be attached to the wall asembly 18. Wall assemblies 12 and 20 are shown in FIGURE 9 and these wall assemblies have a substantially rectangularly shaped in elevation. The wall assemblies 12 and 20 have a height which is equal to the height of the large end of the tapered wall assemblies 14 and 18.

FIGURE 10 illustrates the wall assembly 22 which provides the opposite end of the pool. It will be understood, the wall assembly 22 has the same height as the wall assemblies 12 and 20 and the same length as the wall as sembly 16.

Since the panel-like wall assemblies are substantially identical with regards to the concept of the present invention, a description of one wall assembly will suffice for all wall assemblies. Referring now to FIGURES l, 2 and 6 the end wall assem ly 16 is shown with the metallic rectangularly shaped panel 42. Panel 42 is provided with a flanged upper longitudinal edge 46 which is integral therewith and is adapted to fair with a concrete deck 48 of the swimming pool 10. The panel 42 is provided with a plurality of longitudinally spaced vertically extending stiffening plate members or buttresses t). Extending along the lower longitudinal edge of the panel 42 is a flange like bottom plate 52. The vertical reinforcing plates 50 and the bottom plate 52 are welded to each other as well as to the panel 42 soas to make a strong substantially rigid unit.

The vertical reinforcing wall stiffening plates 50 provide .a means for anchoring an upwardly facing C shaped channel element 54. It will be noted in FIGURE 2 that the channel element 54 is welded on one of its flanges as indicated at 56 to each of the vertical stiffening plates 56. A U shaped rod 58 extending about the C shaped channel element 54- and Welded at its ends to the plate 50 as indicated at 66 helps support the channel element. The rod 58 is also welded to the other flange of the channel element 54 as indicated at 62. A plurality of longitudinally extending reinforcing rods 64 extend along the wall assembly and are secured to the outer edge of the plates 5% The uppermost reinforcing rod 64 is utilized as an anchor means for mesh reinforcing rods 66 used in the construction of deck 48. As is now evident, once the prefabricated wall assembly 16 has been erected and attached to other wall assemblies to form a water tight enclosure and after the concrete bottom 23 has been poured, the channel element 54 provides added support for the deck 48 at the pool edge as well as giving the panel 42 sufficient strength.

Suitable U shaped clamps 68 anchored to brackets 70 supported on the vertical plates 50 provide means for holding a tubular conduit 72 which is connected to and runs from the skimming means 32 to a recirculating filter system generally indicated at 74 in FIGURE 1.

A hook shaped rod 76 welded to the lower end of each of the vertical plates 50 provides a means for tieing the reinforcing mesh tie rods 78 used in construction of the concrete bottom 23. After the tie rods 78 have been secured to the hook shaped rods 76, the concrete for the bottom 23 may be poured, and as shown in FIGURE 2, will securely anchor the wall assemblies, such as the wall assembly 16, in place. Of course, it will be understood that in the deep end portion 26 of the pool 10, the mesh 78 will slant downwardly and away from the respective panels so that the bottom 23 is effectively concave in this portion of the pool.

Each of the wall assemblies 12, 14, 14, 16, etc., is provided with at least two jack assemblies 80, one being adjacent to each end thereof. The jack assemblies 30 of the wall assemblies provide a means of supporting the wall assembly during erection of the same and also a means of leveling the upper longitudinal edge of the Wall assembly so that when one wall assembly is erected next to another wall assembly, the assemblies may be easily adjusted with respect to one another to align and position them properly 80 that they may be joined together to provide a watertight enclosure. The jack assemblies 80 include a flat base plate 82 having an upwardly extending collar 84 thereon. A jack screw 86 is adapted to be rotatably supported in the collar 84. The bottom flange-like plate 52 is provided with an aperture 88 therethrough, and a nut 90 is welded to the plate 52 in alignment with the aperture 88, as indicated at 92. The jack screw 86 is threadedly received by the nut 90. In order that the jack screw may be rotated in the collar 84 to adjust the panel 42 vertically, a nut 92 is welded to the jack screw 86 as shown in FIGURE 2.

It will now be obvious by referring to FIGURE 2 that when the wall assemblies such as the wall assembly 1-6 are positioned in an excavation 100, the wall assemblies may be adjusted vertically from the inside of the panels by application of a wrench to the nut 92. Such a construction provides for erecting the wall assemblies closer to the vertical edge of the excavation and therefore it is not necessary to provide as much back fill or to excavate a hole considerably larger than the dimensions of the desired pool or tank construction.

In assembly of tanks such as the swimming pool 10 from the wall assemblies just previously described, the wall assemblies 12, 14, I4, etc., are arranged in the excavation 1% and then each wall assembly is individually adjusted to align it properly with its adjacent wall assembly. Once the vertical adjustments of the wall assemblies have been made they are supported by the jack assembly 8t) and each wall assembly is then secured to its adjacent wall assembly. After the wall assemblies have been secured together to provide water tight joints, then the tie rod mesh 7%; is connected to the hooks 76 and the concrete bottom 23 is poured and allowed to set. After pouring of the concrete bottom 23, back fill, if desired and necessary, may be placed behind the panels 42 of the wall assemblies and the pool deck 48 is then poured.

When it is desired to erect a tank for use above ground, it is not necessary to provide the tank with a concrete bottom. Referring now to FIGURE 11, a modification of the present invention is illustrated. In FIGURE 11 the Wall assembly 16' is shown with the same type of jack assembly for adjustably supporting the same on the surface of the ground 102. The wall assembly 16 and the other wall assemblies (not shown) making up the tank are adjusted relative to one another by the jack assemblies 84} and once they have been adjusted, then the tank is provided with a steel bottom 23' which is suitably Welded as indicated at 104 to the lower longitudinal edge portions of all of the panels of the wall assemblies. After the bottom 23' has been welded to the wall assemblies as just described, a suitable protective coating may be sprayed over the bottom at the welds and then the space between the ground I02 and the bottom may be filled with dirt, concrete or the like. It is not desirable to use a metallic bottom in a tank construction which is erected in an excavation as the welding of the tank bottom to the side wall assemblies would destroy the protective coating on the surface next to the excavation. There would be no way of applying other protective coating to the area where the welding caused the coating to be destroyed. Consequently such tanks having metallic bottoms are prefen ably erected above ground.

Referring now to FIGURES 3, 4 and 5, an improved expansible joint for prefabricated wall assemblies is illustrated. In large tanks or pools the panels of the wall assemblies cannot in themselves compensate for all expansion and contraction caused by variations in temperature or shifting of the ground. In some instances the expansion and contraction in the wall assemblies is not even, and such uneven stresses and strains are highly undesirable, especially at the joints between the wall assemblies, as they oftentimes cause cracks and the like resulting in leakage of the tank structure at the joint. It has been found highly advantageous to provide expansible joints 40 between at least some of the wall assemblies making up the tank.

In more detail and referring to FIGURE 3, it will be noted that the expansible joint 40 is provided between wall assemblies 18 and 20. 'To obtain such a joint, the

wall assemblies 18 and 20 are provided with flanged ends 106 and 108 respectively. Instead of providing individual jack assemblies at the ends of the wall assemblies 18 and 20, where the expansible joint 40 is to be utilized, a jack assembly 110 is provided. This jack assembly includes an elongated rectangular ground supporting plate 112 having sufficient length to extend beneath each of the wall assemblies 18 and 2t) and a pair of jack screws 114 and 116 extending through the longitudinal bottom flangelike plate 52 of each of the wall assemblies. The screws 114 and 116 are adapted to be supported and rotate in the collars 118 and 120 respectively and extend through nuts (not shown) secured to the bottom plates 52. Just as in the description of the jack assemblies 80, the jack assembly 110 may be operated from the inside of the tank structure by applying a wrench to the operating nuts 122 and 124. When the two wall assemblies 18 and 29 have been erected and suitably leveled by the jack assembly 110, a bar 126 is placed between the flanges 106 and 108, the bar being positioned adjacent the outer free ends of the flanges 106 and 1&3. Nut and bolt assemblies 128 are used to bolt the bar in place. Once the bar has been bolted in place, then the bar 126 is welded to both of the flanges 108 and 166. The bar 126 provides a space between the flanges 106 and 108 on the inner side of the panels of the wall assemblies 18 and 20. Bar 126 may be prepositioned at time of fabrication to either flanges 108 or 106, thereby reducing the field labor to just one vertical weld. The expansion joint 40 may be provided with flanges N6 and 108 spaced apart by means other than the bar 126. An example would be provision of an offset edge on one or both of the flanges requiring only one weld. The space between the flanges 106 and 198 may be filled with a suitable pliable material such as pitch epoxy resins, rubber, rubber substitutes or the like and a resilient member 130 such as a tubular hose or the like may be provided between the wall assemblies 18 and 20 to enclose the filler means and provide a smooth clean joint. As shown in FIGURE the C shaped channel elements 54 are cut on a bias at their ends as indicated at 132 so as not to interfere with expansion or contraction at the joint 40.

By providing the bar 126 welded to the free ends of the flanges 106 and 108, the wall assemblies 18' and 26 can pivot about the bar 126 and the filler means, namely the pitch, will compensate for the movement of the panels relative to one another.

The tank construction heretofore described provides for the easy and accurate erection and joining together of the prefabricated wall assemblies prior to construction of the bottom of the tank. The use of the jack assemblies on each of the prefabricated wall assemblies enables erection by unskilled personnel in that no special jigs or supports are necessary to position accurately and hold the panels prior to connecting the panels of the assemblies together. All adjustment and leveling of the wall assemblies may be accomplished from within the enclosure defined by the wall assemblies and consequently the excavation need not be extra large nor is it necessary to provide a lot of back fill behind the panels. By providing the expansible joints in the tank construction, the completed tank can have expansion and contraction caused by variation in temperature without affecting the joints between the wall assemblies. While the tank has been described in connection with the design of a swimming pool, it is easily seen that the tank construction may be utilized for a reservoir, a filter plant, or sewage plant, and in such instances, it is not necessary to provide cutouts in the panels of the wall assemblies for skimming means and the like.

that the swimming pool disclosed therein is provided with skimmer means 32 for skimming the surface water and returning the same to the recirculating filter means generally designated at 74. The handrail 38 which encompasses at least a portion of the perimeter of the pool above the normal water level therein is connected into the filtering system 74 and is utilized to return the filtered water to the pool, in the novel manner described.

Each of the wall assemblies 12, 14, 14, 16 etc. is provided with a section 134 of a rigid tubular conduit. Preferably the conduit sections 134 are made of stainless steel. The sections 134 are supported by suitable brackets 136 welded to the inside surface of the respective panels of the wall assemblies. When the wall assemblies are erected and secured together, a flexible tubular coupling member 138 is provided to couple the adjacent ends of the tubular conduit sections 134. At least one of the tubular conduit sections 134 is connected to an outlet 14% (FIGURE 15) from the usual water supply pump of the filtering system 74. The sections of tubular conduit 134 are provided with longitudinal spaced orifices 142 which have their axis on a radius of the conduit which extends downwardly at an acute angle to the side wall of the panels of wall assemblies, 12, 14, etc. As shown in FIGURE 2, the orifices 142 direct jet streams of filtered water at the panels, the streams striking the panels at a point adjacent to the normal level L of water in the pool. When the recirculating system is in operation and water is being withdrawn by the skimming means, filtered and then returned to the pool, the jets of water with the chlorine entrained therein strike the panels of the wall assembly so as to provide a continual motion to the water, thus producing an aesthetic appeal to the swimmers. By supplying the water to the pool in this manner, the safety of the swimmers is also enhanced in that the chlorine entrained in the water being supplied to the pool is furnished at the top surface of the pool. The continual motion of the water in this area eliminates any stagnant areas of surface water and consequently reduces the chance of algae forming in the pool. The jets through the angled orifices 142 impart a washing down effect to the side walls of the swimming pool and aerates the water to clarify the same and suppress the growth of anaerobic bacteria. Because of the location of the handrail at the edge of the pool above the water level of same, splash out of water is controlled, eliminating the possibility of contaminants at the pool edge from being washed back into the pool. A very important function of the jets is to break the water surface tension to permit contaminants on the pool surface to be enveloped into the pool water body in order to be controlled by the chemical additives. In addition, the provision of the conduit having sufiicient rigidity so that the conduit may be used by swimmers as a handrail, protects the swimmers in getting in and out of the pool so that they do not contact contamination present in the scum gutter.

Referring now to FIGURES 12, 13 and 14, the improved skimming means 32 is shown in detail. It has een found that the majority of pool water contamination is embodied in the top in the water surface film of pool surface film. In recent years, surface skimmers have been placed in the side wall of the swimming pools, there being about one surface skimmer for every five hundred square feet of surface area. A constant supply of Water passes through the skimmer to the filters and then is returned to the pool. In the present invention, the improved skimming means 32 includes a skimmer weir made of stainless steel which is pivotally mounted at its lower end, as indicated at 152 in a sump 154, adapted to receive water from the pool through a passage 156. The outer free end of the weir plate 150 is curved on an axis parallel to the pivotal axis of the plate, as indicated at 156. At least one cylindrically-shaped, buoyant float 153 is adapted to fit into the curved free end portion of the weir 150. By designing the weir 150 in the manner just previously described, the buoyancy to govern the angle of the weir 150 may be controlled by utilizing any desired 9 number of floats 158, as shown in FIGURE 13. When it is desired that the recirculation of water be f ster, th buoyancy is decreased by removing one or more of the float elements 158, and conversely when the situation demands less recirculation of the water, then the buoyancy of the Weir is increased. By providing :a weir in the skimmer passage 156, any debris or dirt removed from the surface of the pool cannot flow back into the pool.

Water received in the sump 154 is supplied by the passage 159 to the previously described conduits 72, which in turn supplies the water to the recirculating filter system 74. The water is supplied from the skimmers and the main drain 30 to filter tank wet well 161 through conduits 167 and 169 respectively. The filter plates 162. filter the water and return the same to a pump unit 164 where it is pumped back through the conduit 140 and handrail 134 into the pool.

A novel slurry tank arrangement is disclosed in FIG- URE 15. The slurry tank 160 is provided with .diatomite and in order to keep the diatomite constantly in suspension with the water entering the slurry tank through the pipe 166 connected to the pump discharge, an impeller 168 is mounted for rotation on a motor 170. The impeller 168 which rotates within the tank 160 continually agitates the water in the slurry tank and mixes the same with the diatomite so that the water having the diatomite in suspension therewith can provide additional filter coating of diatomite on the filter plates 162 by flowing over the walls of slurry tank into the Wet well 161. When sufficient diatomite builds up on the filter plates, they may be easily removed, cleaned and then replaced.

The specific embodiments described have been shown merely for the purposes of illustrating the principles of the invention and to disclosed structure which has fully and efiectively accomplished the objects and advantages of the invention. Therefore, the terminology used in the specification is for the purpose of description and not limitation, the scope of the invention being defined in the claims.

We claim:

1. A tank construction comprising: a bottom and a plurality of prefabricated wall assemblies extending from the bottom to the rim of the tank; joint means connecting said wall assemblies together to form a liquid-tight enclosure; and jack means carried by said wall assemblies for adjustably supporting each of said wall assemblies as the same are being erected and prior to connection of said wall assemblies together by said joint means, said jack means including a rotatable jack screw, a flat ground engaging plate member having an upwardly extending collar for rotatably receiving and supporting said jack screw, means carried by said well assemblies for threadedly receiving said jack screw and raising and lowering the same when said jack screw is rotated, and means carried by said jack screw below the lower edge of said wall assemblies for rotating said jack screw from the inner side of said wall assemblies.

2. A tank construction as in claim 37 wherein said joint means is an expansion joint including a flange rigidly connected to the end of each of said wall assemblies, said flange extending outwardly of the wall assembly away from the inner side thereof, and means to connect the outer ends of adjacent flanges together with the flanges and their inner ends in spaced relationship to each other.

3. A tank construction as in claim 2 wherein said connecting means includes a bar member welded to adjacent flanges along their free ends.

4. A tank construction as in claim 2 wherein the space between the end flanges of adjacent wall assemblies is filled with a pliable material and wherein a resilient member is positioned between adjacent wall assemblies and encloses the pliable material.

5. A tank construction comprising: a bottom and a plurality of prefabricated wall assemblies extending from the bottom to the rim of the tank; joint means connecting said wall assemblies together to form a liquid-tight enclosure; and jack means carried by said wall assemblies for adjustably supporting each of said wall assemblies as the same are being erected and prior to connection of said wall assemblies together by said joint means, said jack means including a flat ground engaging plate member extending beneath ends of adjacent wall assemblies, said plate member having at least a pair of upwardly extending collars, a jack screw rotatably receivedin each collar of said plate member, means carried by each end of adjacent wall assemblies for threadedly receiving the respective jack screws, and means carried by each of said jack screws below the lower edge of said wall assemblies for rotating said jack screws individually from the inner side of said Wall assemblies whereby said Wall assemblies may be adjusted vertically with respect to each other.

6. In a tank construction wherein the side walls of the tank are made from a plurality of prefabricated metallic panels erected and connected together to form a watertight enclosure having a bottom, the improvement in joint construction between ends of adjacent panels comprising a flange rigidly connected adjacent the end of each adjacent panel, each flange extending transverse to the plane of and outwardly of the panel to which it is connected, means connecting the outer ends of the opposed flanges of adjacent panels rigidly together with a space being provided between the opposed flanges and ends of adjacent panels, and pliable filler means filling the space between opposed flanges to allow for movement between adjacent panels caused by expansion and contraction.

7. A tank construction defined in claim 6 wherein said filler means is epoxy resin.

8. The tank construction of claim 6 including a resilient member extending between adjacent panels from the bottom to the top and enclosing said filler means.

9. The tank construction of claim 6 wherein said con necting means includes a bar positioned between the opposed flanges adjacent their outer ends, said bar being rigidly secured to each of said flanges.

10. In a tank construction wherein the side walls of the tank are made from a plurality of prefabricated metallic panels erected and connected together to form a watertight enclosure having a bottom, the improvement in joint construction between adjacent panels comprising a flange rigidly connected adjacent the end of each of the adjacent panels, each flange extending transverse to the plane of and outwardly of the panel to which it is connected, means carried by said panels for supporting and adjusting the adjacent panels vertically with respect to each other during the erection of the joint construction, means connecting the outer ends of the opposed flanges of adjacent panels rigidly together with a space being provided between said flanges and the ends of adjacent panels, said connecting means being made after operation of said support and adjustment means, and filler means filling the space between the opposed flanges to allow for movement between the adjacent panels caused by expansion and contraction.

11. The joint construction of claim 10 wherein said support and adjustment means for the joint construction includes a ground engaging plate extending beneath at least a portion of each of the adjacent panels, and jack means associated with each adjacent panel and with said ground engaging plate member.

12. A joint construction defined in claim 11 wherein said jack means includes a first jack screw rotatably supported in said ground engaging plate member, means carried by one panel for threadedly receiving said jack screw, a second jack screw rotatably supported by said ground engaging plate and means carried by the adjacent panel for threadedly receiving said second jack screw.

13. A joint construction of claim 12 wherein each or" said jack screws is provided with means below the lower edge of the respective panels whereby said jack screws 1 1 may be operated to raise and lower the panels from the inside of the panels.

14. In a swimming pool having a system for filtering and recirculating the water in the pool by utilizing a surface skimming means of the type having a sump in communication by a passage way with the top of the pool for withdrawing water from the pool surface; the improvement comprising: a skimmer weir, said skimmer weir including a flat metal plate pivotally connected at its lower end to the bottom of the passage way, said flat metal plate having its upper free end portion curved on an axis parallel to the pivotal axis of the plate, and at least one cylindrically shaped buoyant float detachably carried in the curved portion of the free end.

15. A filter system for use in recirculating and purifying water of a swimming pool comprising: skimming means in communication with the top of the pool for withdrawing water from the pool surface, a slurry tank having an open top and at least one wall for overflow therefrom, said slurry tank containing diatomite and being adapted to receive filtered water, agitating means in said slurry tank, filter means positioned below said slurry tank for directly receiving the overflow therefrom, said filter means having an outlet for filtered water in communication with an inlet to the pool.

16. A structure as defined in claim 15 wherein said agitating means in said slurry tank includes an impeller rotatably mounted therein adjacent the bottom and operable to maintain the diatomite in a suspension with filtered water flowing into said slurry tank.

17. The structure defined in claim 15 wherein said skimming means includes a weir, said weir being a flat metal plate pivotally connected at its lower end and having its upper free end portion curved on an axis parallel to the pivotal axis of the plate, and at least one cylindrically-shaped buoyant float detachably carried in the curved portion of the free end.

18. A prefabricated wall assembly for use in constructing tanks comprising: an elongated steel panel adapted to form at least a portion of a substantially vertical wall of the tank, said panel having a first flange extending along its longitudinal upper edge and a second flange extending along its longitudinal lower edge, said panel being provided with jack means adjacent each of its ends and its lower longitudinal edge, each of said jack means including a ground engaging plate having an upwardly extending collar thereon, a jack screw receivable in said collar and rotatably supported thereby, and means carried by the lower flange of said panel for threadedly receiving said jack screw and raising and lowering the panel when said jack screw is rotated.

19. A tank construction comprising: a plurality of prefabricated wall assemblies; each of said wall assemblies including a panel having a flange extending along its upper longitudinal edge and a second flange extending along its lower longitudinal edge and a plurality of longitudinally spaced vertical stiffening plates carried between said flanges; means for joining said panels together to form a liquid-tight enclosure; a plurality of J-shaped hooks, one being secured to each stiffening plate adja- 12 cent its lower end and depending downwardly therefrom beneath the lower longitudinal edge of said panel and having its hook portion opening away from the face of the panel; a reinforcing steel mesh secured to said J-hooks; and a concrete bottom having said J-shaped hooks and said reinforcing steel mesh embedded therein.

20. A tank structure comprising: a bottom; a plurality of prefabricated wall assemblies secured to each other and to said bottom to define a water-tight enclosure, each of said wall assemblies including a metal panel having a flange extending along its upper longitudinal edge and a second metal flange extending along its lower longitudinal edge and a plurality of longitudinally spaced vertical stiflening plates carried between said flanges, an elongated channel-shaped element rigidly secured to each of said vertical stiffening plates and extending longitudinally of the panel and facing upwardly; back fill beneath said channel-shaped element; and a concrete deck extending about the periphery of said tank, said deck having a portion adjacent the periphery of said tank directly supported on the channel-shaped elements of each of said panels.

21. A swimming pool construction having a bottom and side walls defining a water-tight enclosure and means for supplying water to the pool comprising: a horizontally extending tubular conduit attached to the walls of the pool and spaced outwardly from the walls and above the normal level of water in the pool, said tubular conduit being connected to the means for supplying water to the pool, said tubular conduit having a plurality of discharge orifices therein and spaced longitudinally thereof, each of said orifices having an axis extending at an acute angle to the walls of the pool and arranged to intersect the walls of the pool at or beneath the level of water in the pool whereby water discharging through the orifices is directed downwardly at an angle to and against the walls at a position at or below the normal level of water in the pool.

22. The structure defined in claim 21 wherein said tubular conduit is rigid and provides a hand rail for said pool.

References Cited in the file of this patent UNITED STATES PATENTS 898,415 Merralls Sept. 8, 1908 1,854,443 Barce Apr. 19, 1932 2,169,274 Mills Aug. 15, 1939 2,446,323 Davis et al. Aug. 3, 1948 2,488,708 Clemetsen Nov. 22, 1949 2,490,272 Kascle Dec. 6, 1949 2,701,235 King Feb. 1, 1955 2,803,835 Summers Aug. 27, 1957 2,809,752 Leslie Oct. 15, 1957 2,826,307 Pace Mar. 11, 1958 2,844,255 Cavenah et al. July 22, 1958 2,932,397 Ogden Apr. 12, 1960 2,957,580 Hunziker Oct. 25, 1960 FOREIGN PATENTS 601,341 Great Britain May 4, 1948 

